BUG #11603: replication, pg_basebackup and high load

The following bug has been logged on the website:

Bug reference: 11603
Logged by: Michiel
Email address: mdglange(at)gmail(dot)com
PostgreSQL version: 9.4beta2
Operating system: Linux
Description:

The test I did involved the following: a master database with two slaves. On
the master two replication slots have been configured as per the
documentation. One slave active before I put some "heavy" load (the
environment is scaled such, that inserting a few gigabytes of insert
statements is a heavy load. This is on purpose)

During this load I started a pg_basebackup from the master, immediately
followed (pg_basebackup && mv recovery.conf $PG_DATA/ && pg_ctl start) by
placing the prepared recovery.conf and starting this slave. The
pg_basebackup took a few hours (as expected) but starting this latter slave
would not work because the WALs were no longer available.

I'd expect to see that pg_basebackup restores up to the last WAL, so that
regardless of the load and changes done on the (master) database replication
picks up.